Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Ionic effects on amiloride block of the mechanosensitive channel in Xenopus oocytes.
Lane JW
,
McBride DW
,
Hamill OP
.
???displayArticle.abstract???
1. Patch clamp techniques were used to measure the ionic dependence of amiloride block of single mechanosensitive (MS) channels in frog (Xenopus laevis) oocytes. 2. The primary aim was to determine whether the difference in potency of amiloride block of MS channels in frog oocytes (IC50 = 0.5 mM) and chick auditory hair cells (IC50 = 50 microM) was due to the different ionic recording solutions. 3. Amiloride block of the oocyte MS channel does not vary significantly with complete substitution of external Na+ (i.e. 100 mM) with K+ in Ca(2+)-free recording solution (in both Na+ and K+ the IC50 = 0.5 mM). 4. A physiological concentration (1.8 mM) of external Ca2+ blocks the oocyte MS channel and reduces the potency of amiloride block (IC50 = 1.1 mM) without altering the voltage-dependence or the HIll coefficient (n = 1.8) of amiloride block. The reduction in potency can be explained by surface charge screening by Ca2+ which reduces the effective amiloride surface concentration. 5. The present results indicate that factors other than ionic recording conditions must underlie the difference in potency of amiloride block of MS channels in oocytes and auditory hair cells.
Benos,
On the mechanism of the amiloride-sodium entry site interaction in anuran skin epithelia.
1979, Pubmed
Benos,
On the mechanism of the amiloride-sodium entry site interaction in anuran skin epithelia.
1979,
Pubmed
Corey,
Ionic basis of the receptor potential in a vertebrate hair cell.
1979,
Pubmed
Crawford,
The actions of calcium on the mechano-electrical transducer current of turtle hair cells.
1991,
Pubmed
Cuthbert,
The role of calcium ions in the interaction of amiloride with membrane receptors.
1972,
Pubmed
Desmedt,
Amiloride blockage of Na+ channels in amphibian epithelia does not require external Ca2+.
1991,
Pubmed
Garty,
Characteristics and regulatory mechanisms of the amiloride-blockable Na+ channel.
1988,
Pubmed
Hamill,
Amiloride: a molecular probe for mechanosensitive channels.
1992,
Pubmed
Hamill,
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.
1981,
Pubmed
Hille,
Negative surface charge near sodium channels of nerve: divalent ions, monovalent ions, and pH.
1975,
Pubmed
Howard,
Mechanoelectrical transduction by hair cells.
1988,
Pubmed
Jørgensen,
Amiloride blocks the mechano-electrical transduction channel of hair cells of the chick.
1988,
Pubmed
Lane,
Structure-activity relations of amiloride and its analogues in blocking the mechanosensitive channel in Xenopus oocytes.
1992,
Pubmed
,
Xenbase
Lane,
Amiloride block of the mechanosensitive cation channel in Xenopus oocytes.
1991,
Pubmed
,
Xenbase
Methfessel,
Patch clamp measurements on Xenopus laevis oocytes: currents through endogenous channels and implanted acetylcholine receptor and sodium channels.
1986,
Pubmed
,
Xenbase
Taglietti,
A study of stretch-activated channels in the membrane of frog oocytes: interactions with Ca2+ ions.
1988,
Pubmed
Yang,
Block of stretch-activated ion channels in Xenopus oocytes by gadolinium and calcium ions.
1989,
Pubmed
,
Xenbase
